Generally, an inverter is an inverse conversion device that electrically converts DC to AC. An inverter used in the industry is defined as a series of devices that control the motor speed to be used with high efficiency by receiving the power supplied from the commercial power supply and varying the voltage and frequency by itself and supplying the varied power to the motor. Such inverter is used in various forms throughout the industrial field including fans, pumps, elevators, transport devices, and production lines.
Inverters include heat emission elements such as high-frequency switching elements such as insulated gate bipolar transistors (IGBTs), or metal oxide semi-conductor field effect transistors MOSFETs, and high-capacity capacitors. A cooling device, such as the fan for cooling the exothermic component is essential to ensure the life of the inverter and provide reliability.
When a problem occurs with this cooling device, an inverter controller detects the failure of the cooling device. When a trip occurs, the controller may stop of supply of a pulse width modulation to the inverter and stops the inverter operation. However, since the operation of the inverter stops due to the detection of the failure of the cooling device in an inappropriate state, the reliability of the inverter system is deteriorated.